JPH0641618A - Method and device for continuously producing active metal powder - Google Patents

Abstract

PURPOSE:To continuously produce the powder of an active metal without contaminating the powder. CONSTITUTION:A coarse-grain or small-piece active metal (e.g. Ti and Ti alloy) is melted as raw material M1, a rod-shaped solidified material M3 is formed and continuously withdrawn, the tip is melted, and the falling molten metal M4 is atomized to produce an active metal powder M5 (e.g. Ti powder).

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method and apparatus for producing active metal powders such as Ti and Ti alloys, more specifically, melting,
The present invention relates to a method and a device for producing a fine and high-purity powder by causing a flowing active metal to spray a flowing active metal.

[0002]

2. Description of the Related Art As one of the methods for producing metal powders used in powder metallurgy and the like, an atomized powder production method is used in which a molten metal is made to flow down, and a fluid such as air or water is caused to act on the metal to be powdered. ing. The conventional atomized powder manufacturing method is to use a refractory pan such as zirconia, alumina, or carbon, a drip hole provided at the bottom of the crucible, or a molten metal to flow down the molten metal and spray the fluid at high speed. It is a method of spraying.

However, when applying the atomized powder manufacturing method using the above-mentioned refractory saucer, molten metal nozzle, etc. to the powdering of active metals such as Ti and Ti alloys,
Since the active metal in the molten state comes into direct contact with the refractory, elements such as oxygen and carbon in the refractory react with the active metal, or are mixed into the active metal, and the produced powder product is contaminated, or It is difficult to manufacture high-purity active metal powder due to problems such as shortening the life of refractory materials.

Therefore, as a method for producing atomized powder of an active metal, a molten metal is directly dropped from a dropping hole provided in a cooled metal crucible without using a refractory pan or a molten metal nozzle. Alternatively, a method has been studied in which a rod material is used as a raw material and the tip is melted by high-frequency heating and the dropping molten metal is atomized with an inert gas.

However, in the method of directly dropping the molten metal from the dropping hole of the cooled metal crucible, the temperature of the molten metal is lowered or solidified because the molten metal is cooled in the dropping hole. The flow of molten metal falling from the hole becomes unstable, and the temperature of the molten metal immediately before being atomized is low, so the viscosity of the molten metal increases, and compared with the case of using a refractory pan or a molten metal nozzle, atomization Sometimes it is necessary to inject the atomizing fluid with a larger pressure, and it is difficult to improve the atomizing efficiency.

In the method of melting the tips of the rods, it is difficult to improve the productivity because it is necessary to replace the raw rods, and the holding portion of each rod remains as a residual material after each exchange, so that the yield is increased. Cause a decrease in

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and provide a method and apparatus for continuously producing a clean and fine active metal powder mainly used in powder metallurgy and the like. And

[0008]

The gist of the present invention resides in the following continuous production method of active metal powder and continuous production apparatus thereof.

[0009] The active metal is characterized in that the active metal is melted and continuously drawn while being formed into a rod-shaped solidified product, the withdrawn tip portion is melted, and a spray fluid is made to act on the flowing molten metal to spray it. Continuous production method of powder.

A primary melting device for melting the active metal;
A mold for solidifying a molten active metal into a rod shape, a pulling mechanism for continuously pulling out the solidified rod-shaped body, a remelting device for melting the tip end of the pulled-out rod-shaped body, and a molten metal flowing down and sprayed. A continuous production apparatus for active metal powder, which comprises a spraying apparatus.

In addition to Ti and Ti alloy, the above-mentioned active metals include
Zr, Ta, Nb, and other metals that easily react with oxygen and refractories (SiO ₂ , Al ₂ O _3, etc.). As the shape of the active metal to be subjected to the initial dissolution, coarse particles or small pieces are relatively easy to obtain, and the solubility and the handling property are good and suitable, but the dissolution is not so difficult and the handling is easy. The shape is not limited to this shape as long as there is no problem with the sex.

If an inert gas such as Ar gas or He gas is used as the atomizing fluid, the produced metal powder can be prevented from being contaminated.

FIG. 1 is a vertical cross-sectional view showing an arrangement of an apparatus for carrying out the method of the invention described above, that is, an example of the apparatus of the invention described above. In the figure, 2 is a raw material charging device 1
From the primary melting chamber 8 for melting the raw material M1 is melted by the primary melting device to melt the primary molten metal M2 into a rod-shaped solidified product M3, and 4 is the rod-shaped solidified product M3. A drawing mechanism 5 for continuous drawing is provided in the remelting chamber 9, a remelting device for melting the tip of the rod-shaped solidified matter M3, and 6 is a melted rod-shaped solidified matter M3.
Is a spray nozzle that sprays a spray fluid onto the molten metal flow M4 flowing down from the tip of the. The mold 3 is made of metal and is water-cooled. Also, 10 is an atomizing chamber, 7
Is a gas discharge port provided on the side of the atomizing chamber 10, and a powder collecting device 12 for collecting the manufactured powder is attached to the lower portion of the atomizing chamber 10.

As the primary melting device 2, a melting device using a plasma arc or an electron beam, a high frequency induction heating device, or the like can be used.

If the pulling mechanism 4 is of a roller type, continuous pulling can be performed.

As the remelting device, a melting device utilizing a plasma arc, a high frequency induction heating device or the like can be used. When the high frequency induction heating device is used, it is easy to uniformly dissolve the tip of the rod-shaped solidified matter M3.

As the spraying device, a commonly used device can be applied.

[0018]

In order to produce an active metal powder using the apparatus shown in FIG. 1, first, a coarse-grained or small-piece active metal raw material M1 such as titanium sponge is fed from the raw material charging device 1 into the primary melting chamber 8. Is continuously supplied to the mold 3. The atmosphere in the chamber 8 is a high vacuum atmosphere for electron beam melting, and an Ar gas atmosphere or a reduced pressure atmosphere of Ar gas (20 to 200 Torr) for plasma arc melting or high frequency induction melting.

The supplied raw material M1 is melted by the primary melting device 2 to become a primary molten metal M2. The primary molten metal M2 is cooled by the wall surface of the metal mold 3 to become a rod-shaped solidified substance M3,
It is pulled down by the pulling-out mechanism 4. The pulling-out mechanism 4 can give rotation to the rod-shaped solidified matter M3 about the vertical line in the longitudinal direction, and can uniformly dissolve the rod-shaped solidified matter M3 at the time of re-melting. The lower end of the rod-shaped solidified material M3 that has been pulled down is melted by the remelting device 5, and the molten metal flows down as a molten metal flow M4. The molten metal flow M4 that has flowed down is pulverized and cooled by an inert atomizing fluid such as Ar gas or He gas that is atomized at a high speed from the atomizing nozzle 6, and then falls and falls as powder M5 as a powder recovery device 12 (collection bottle). Etc.). The fine powder is collected by a cyclone (not shown) provided at the gas outlet 7.

As described above, in the method or apparatus of the present invention, the active metal having a relatively easily obtained shape such as coarse particles or small pieces is used as a raw material, and melting, solidification, drawing, remelting and pulverization are continuously performed. Then, a clean and fine active metal powder can be obtained.

[0021]

Example: Sponge Ti having the composition shown in Table 1 as a raw material M1
A Ti powder production test was conducted using an apparatus having the configuration shown in FIG.

A plasma torch having an output adjusted to 50 kW was used as the primary melting device 2, and a high frequency induction heating device having an output of 40 kW and a frequency of 360 kHz was used as the remelting device 5. Ar gas with a pressure of 0.98MPa was used as the atomizing fluid, and the inner diameter of each nozzle was 0.9mm.
And these nozzles are evenly spaced on the circumference of a circle with a diameter of 25 mm.
Individually arranged nozzles were used.

First, the raw material is depressurized from the raw material charging device 1.
It was put into the primary melting chamber 8 held at (350 mmHg), and was irradiated with Ar plasma arc in the primary melting apparatus 2 to melt it to obtain a primary molten metal M2. Then, in a water-cooled copper mold 3, a rod-shaped solidified product M3 was obtained by solidifying and molding into a round rod shape with a diameter of 50 mm.
And the rod-shaped pull-out mechanism 4 causes the rod-shaped solidified matter M3
While being rotated at a rotation speed of 8 rpm about the vertical direction, it was pulled vertically downward and fed into the remelting chamber 9 and melted by the remelting device 5. For the flowing molten metal flow M4
When Ar gas was sprayed for 6 hours of continuous operation, Fig. 2
180kg of powder with the particle size distribution shown in and an average particle size of 50μm
was gotten.

The chemical composition of this powder was almost the same as the chemical composition of the raw material as shown in Table 2, and no contamination was observed during the powder manufacturing process.

[0025]

[Table 1]

[0026]

[Table 2]

[0027]

By using the method and apparatus of the present invention, powders of active metals such as Ti and Ti alloys can be continuously produced. According to this method, the product powder is not contaminated during the manufacturing process, and the productivity can be improved as compared with the conventional method.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing the configuration of an example of the device of the present invention. FIG. 2 is a graph showing the particle size distribution of the Ti powder obtained by the method of the present invention.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kenji Yamazaki 1 Higashihama-cho, Amagasaki-shi, Hyogo Osaka Titanium Manufacturing Co., Ltd.

Claims (2)

[Claims] 1. An active metal is melted and continuously drawn out while being formed into a rod-shaped solidified material, the drawn out tip is melted, and sprayed by causing a spraying fluid to act on the flowing molten metal. Continuous production method of active metal powder. 2. A primary melting apparatus for melting an active metal, a mold for solidifying a molten active metal into a rod shape, a pulling-out mechanism for continuously pulling out the solidified rod-shaped body, and a tip portion of the pulled-out rod-shaped body. A continuous production apparatus for active metal powder, comprising a re-melting apparatus for melting and a spraying apparatus for spraying the molten metal which is melted and flows down.